Method of fabricating metal building frame truss units



C. PRUDHON Aug. 8, 1961 METHOD OF FABRICATING METAL BUILDING FRAME TRUSSUNITS 5 Sheets-Sheet 1 Original Filed Jan. 6, 1956 Mark Fwd/7022 8, 1961c. PRUDHON 2,994,944

METHOD OF FABRICATING METAL BUILDING FRAME TRUSS UNITS Original FiledJan. 6, 1956 3 Sheets-Sheet 2 Hark Frz/dlmn C. PRUDHON Aug. 8, 1961METHOD OF FABRICATING METAL BUILDING FRAME TRUSS UNITS Original FiledJan 6, 1956 5 Sheets-Sheet 3 [/ir/r Prudhan United States Patent2,994,944 METHOD OF FABRICATING METAL BUILDING FRAME TRUSS UNITS ClarkPrudhon, Pruden Products Co., Evansville, Wis. Original application Jan.6, 1956, Ser. No. 557,796, now Patent No. 2,904,139, dated Sept. 15,1959. Divided and this application Apr. 6, 1959, Ser. No. 804,277

2 Claims. (Cl. 29155) This invention relates to metal frames forbuildings such as warehouses and sheds, and refers more particularly toan improved method of fabricating building frame trusses comprisingspaced apart chords and transverse ties welded thereto and transverselyconnecting them.

More specifically this invention relates to a method for facilitatingthe fabrication, by welding, of trusses whose chords comprisecomplementary L-section chord members which are disposed back to backand are welded to opposite sides of the end portions of the tie membersthat transversely connect the chords.

While the method of this invention may be advantageously employed forthe fabrication, by welding, of such trusses of more general shapes, itis particularly suited for facilitating fabrication of composite trussunits comprising a column-like wall supporting truss section and arafter-like roof supporting truss section joined at an obtuse anglethereto. A truss unit of this latter type forms the basis of mycopending application, Serial No. 557,796, filed January 6, 1956, nowPatent No. 2,904,139, of which this application is a division.

It is the object of this invention to provide a method of fabricatingbuilding frame trusses and truss units of the character described, fromL-section members welded together in such a way as to obviate thenecessity for moving the partially finished truss or unit at any stageduring its fabrication, prior to its completion, and without the needfor making overhead welds or welds in locations which are difficult toget at.

Another object of this invention resides in the provision of a method bywhich a building frame truss or truss unit of the character describedmay be inexpensively manufactured without the necessity for removing itfrom a fixture in which it may be held for Welding until it iscompletely finished.

With the above and other objects in view, which will appear as thedescription proceeds, this invention resides in the novel methodsubstantially as hereinafter described and more particularly defined bythe appended claims, it being understood that such changes in theprecise embodiment of the hereindisclosed invention may be made as comewithin the scope of the claims.

The accompanying drawings illustrate one complete example of the methodfor practicing this invention according to the best mode so far devisedfor the practical application of the principles thereof, and in which:

FIGURE 1 is a perspective view of a building with portions of its wallsand roof cut away to illustrate the manner in which they are suported bytruss unit frames produced in accordance with this invention;

FIGURE 2 is a side elevational view of one of the building frame trussunits per se;

FIGURE 3 is a fragmentary perspective view of an end portion of a trusssection forming part of one complete truss unit;

FIGURE 4 is a fragmentary perspective view of an end portion of anothertruss section of which the truss unit is comprised;

FIGURE 5 is a fragmentary perspective view showing a portion of afixture in which trusses or truss units may be fabricated by the methodof this invention, with Patented Aug. 8, 1961 ICC certain of the chordmembers in position to be placed in the fixture for the first weldingstep;

FIGURE 6 is a fragmentary perspective View corresponding to FIGURE 5 butshowing a portion of the truss unit at an intermediate stage of itsfabrication; and

FIGURE 7 is a view similar to FIGURE 6 but show ing a portion of thetruss unit in substantially finished form and removed from the fixture.

Referring now more particularly to the accompanying drawings in whichlike numerals designate like parts throughout the several views, thenumeral 5 designates generally a building, such as a garage, shed orwarehouse, incorporating building frame truss units fabricated inaccordance with this invention. 7

The truss unit per se, which forms the subject of my copendingapplication Serial No. 557,796, filed January 6, 6, now Patent No.2,904,139, granted September 15, 1959, generally comprises an uprightcolumn portion 9 and a straght roof supporting rafter portion 10connected to the upper end of the column portion and defining an obtuseangle therewith. Both the column and rafter portions 9 and 10 comprisetruss sections having elongated chords 7 connected and braced by ties 8.

As illustrated in FIGURE 1, a building frame comprises a number of thesetruss units extending across the building and spaced along its length,together with lengthwise extending girth strips 11 and purlins 12. Tofacilitate transportion of the frame members, each has its rafterportion 10 constructed in two sections, namely an inner section 13adjacent to and permanently joined to the top of the column portion 9,and an outer section 14 detachably connected to the inner section 13.Preferably the length of the outer section 14 is about twice that of theinner section 13 which is integral with the column portion 9, so thatthe outer rafter section 14 will be of about the same size as theremainder of the truss unit. The rafter sections 13 and 14 may befastened together in endwise abutting relationship by means of tieplates 15 on their chords welded to one of the rafter sections andbolted to their adjoining rafter sections.

It will be observed that the frame units extend across the building inpairs, the units at opposite sides of the roof centerline beingidentical with one another, and the outer ends of the rafter sections 10being joined to one another at the roof centerline. For this purpose anupper tie plate 16 at the top of each unit provides for its connectionwith a similar tie plate on a mating unit at the opposite side of thebuilding, as by means of a bolt or similar fastener engaged in aligningholes 17 in said tie plates.

The lower end of the column portion of each unit is provided with a baseplate 18 by which the unit may be secured to a suitable footing 19, asby means of studs projecting upward from the footing through holes 20 inthe base plate. It will be seen that two truss units (each consisting ofa column portion and connected inner and outer rafter sections) may bereadily fastened together while lying flat on the ground, by means of abolt through their flatwise overlying tie plates 16, and may be readilyerected and secured to a footing.

Girth clips 21 on the outer chords of the column portions and purlinclips 22 on the upper chords of the rafter portions provide forattachment of girth strips and purlins, respectively, which may beordinary 2 X 6 lumber or the like. Both the girth clips and the purlinclips comprise short channel shaped elements having their webs welded orotherwise secured to the chords with their flanges outermost. Nail holes23 in the flanges facilitate attachment of the framing lumber. In thepurlin clips 22 one flange of the channel is relatively short to clear anail driven through the purlin from the other flange.

With the purlins and girth strips in place, any suitable 3 sheet siding24 and roofing 25 may be fastened thereto to finish the building.

The completed truss unit is shown as fabricated entirely from L-sectionmembers, except for attachment fittings (clips, tie plates, etc.).Moreover, each of the truss unit sections has inner and outer chords,each of which chords comprises complementary L-section chord members 27disposed back to back and secured to opposite sides of the tie members,at the end portions of the latter. Thus, the tie members are disposedsubstantially on the median plane of the truss section, so thatimposition of a load on the unit will not set up unevenly distributedstrains therein which might twist or warp it, as would be the case ifthe ties were all disposed to one side or the other of the median plane.

The novel method of fabricating trusses and/ or truss units is disclosedin FIGURES 5 through 7, which fragmentarily show a composite truss unitcomprising a column section 9 and an inner rafter section 13 in variousstages of manufacture. A relatively simple channel-like fixture 26 maybe used in fabricating such a truss unit. The fixture is disposedsubstantially horizontally and has upstanding legs or flanges 28 forsupporting those chord members 27 which are to be secured to one side ofthe ties in relative positions corresponding to those of the chords onthe finished unit. This first set of chord members is held in thefixture with one leg 29 of each chord member disposed substantiallycoplanar (preferably substantially horizontal) with one of the legs ofthe other chord members, and with the other legs 30 of the chord membersprojecting in the same direction (e.g. downwardly) therefrom, to lieflatwise against the inner surfaces of the flanges 28, and restingedgewise upon the bottom of the fixture. These chord members may be heldin said positions by means of tabs 31 struck up from the base or bottomof the fixture, or in other words, tabs 31 cooperate with the flanges 28to confine the legs 30 of the chord members in a vertical position, andthe legs or backs 29 of the chord members in a horizontal position.

The column and inner rafter sections of the unit are thus defined byseparate chord members endwise abutting one another at an obtuse angle,and are butt welded together at their junctions as at 33, with the chordmembers of each of the column and inner rafter sections converging awayfrom said junctions.

From positions above the fixture and the chord members therein, shortertie members 8 are next welded to the first set of chord members 27. Thetie members are held in the fixture by means of clip-like fingers 35 onthe bottom thereof, with each tie member disposed with one of its legs36 in a plane spaced above but substantially parallel to the planecontaining the backs or legs 2-9 of the chord forming members and theother legs 37 of each tie member extending vertically downwardly towardand seating upon the backs 29 of the chord member. The downwardlyprojecting legs 37 of the several tie members are edgewise welded to thehorizontal legs of the chord members therebeneath, at each end of eachtie member, so that every tie extends between and is bonded to bothpairs of the inner and outer chord members 27.

Since the tie member 38 which connects across the junctions 33 of thechord members is subjected to very large compressive loads, it ispreferably fashioned from a pair of L-section members disposed adjacentto one another with their legs projecting in opposite directions and'welded to form a hollow square section. To provide further rigidity andreinforcement at the corner defining the junction of the wall column andrafter portions, one tie member 39 extends straight and unbroken acrossthe inner corner, being fastened at its ends to the outer chord membersand at its middle'to the apex portions of the inner chord members.

Fabrication of the truss unit is then completed in the fixture bywelding a second set of chord members 41 to the ties, again fromlocations above the fixture and the members therein, with the chordmembers of the second set disposed in complementary relation to those ofthe first set. The chord members 41 comprising the second set thereofare arranged back to back with those of the first set, or in other wordswith each chord of the finished unit comprised of two L-section members,each having one of its legs parallel to and spaced from a leg of theother, with the other legs of the two complementary chord memberscoplanar and extending in opposite directions from their parallel legsor backs, and with the ties interposed between and welded to theparallel legs or backs of both pairs of complementary chord members.

Because of the disposition of the ties, the second set of chord members41 may be welded directly to their horizontal legs without necessity forturning the fixture or removing the unit from the fixture and withoutthe necessity for overhead or other diflicult welding op erations.

The tie plates, foot plate, and purlin and girth clips may of coursethen be welded to the structure while it is still in the fixture. Theupper tie plate 16 should be disposed off-center, with one face thereoflying on the median plane of the structure, so that when the tie plateof another unit is secured to it the two units will have coincidingmedian planes and will not have to be warped or twisted during erectionto provide a properly squared up structure. The correct position of theupper tie plate 16 can, of course, be obtained with a suitable spacerblock 43.

The outer rafter-like truss sections are fabricated in similar fashion,in a fixture having locating and supporting flanges for itscomplementary pairs of chord members, which flanges are entirelystraight but converge toward one end of the fixture.

From the foregoing description taken together with the accompanyingdrawings it will be apparent that this invention provides a method forfabricating building frame truss units having elongated chordscomprising pairs of complementary chord members and ties connectedbetween them, all formed from L-section material, wherein the units maybe fabricated in fixtures to assure uniformity, without the necessityfor removing them from the fixtures at any time during fabrication andwithout entailing overhead or other difficult welding opera tions. Itwillalso be appreciated that the method of this invention may bepracticed to advantage regardless of whether the members, andparticularly the chord members, have an L-section or some other crosssectional configuration, such as a channel shape, as long as the chordsare comprised of complementary members arranged back to back and securedto opposite sides of the ties.

What is claimed as my invention is:

1. In the method of making a building frame truss unit having elongatedspaced apart chords connected by ties, which method involves the use ofa fixture for locating and holding the chords in their proper positionsduring fabrication, the characterizing steps of: supporting the fixturein a substantially horizontal position; supporting a pair of elongatedL-section chord members in the fixture in relative horizontal positionscorresponding to those of the chords of the finished truss, but with oneleg of one chord member substantially in the plane of one leg of theother chord member and with the other legs of the chord membersprojecting downwardly, to one side of said plane; welding a plurality ofshorter L-section tie members to said chord members, in positionsbridging the same and with the end portions of one leg of each of saidtie members seating edgewise upon the coplanar legs of said chordmembers, and with the other legs. of said tie members substantiallydisposed in a common second plane parallel to but spaced above saidfirst designated plane; securing other elongated L-section chord membersto the end portions of said tie members, in positions complementary tosaid first designated chord members, by welding portions of one leg ofeach of said other chord members flatwise upon the end portions of thecoplanar legs of said tie members, and so that the other leg of each ofsaid other chord members extends upwardly and lies in the plane of thedownwardly projecting leg of its complementary chord member; andperforming all of said welding operations from positions above thefixture and the members placed therein, while the fixture remains insaid substantially horizontal position.

2. In the method of making a building frame truss unit having elongatedspaced apart chords connected by ties, which method involves the use ofa fixture for locating and holding the chords in their proper positionsduring fabrication, the characterizing steps of: supporting the fixtureat a readily accessible location where welding operations can be easilyperformed therein without involving overhead welding techniques;supporting two chord forming elements that are to have ties secured toone side thereof, in the fixture with said two chord forming elementslocated in the same general plane and in relative positionscorresponding to those of the chords of the finished truss; from saidside, welding said ties to said side of the two chord forming elementsto bridge the same; thereafter welding the remaining chord formingelements to the ties at the side of the latter remote from said twochord forming elements; and performing all of said welding operationsfrom positions opposite said side of the two chord forming elementswhile the fixture remains in said readily accessible location so thatsaid welding operations can be performed entirely from one side of thefixture to obviate the need for turning of the fixture or removal of anyof the partially fabricated truss unit components from the fixtureduring welding.

References Cited in the file of this patent UNITED STATES PATENTS1,549,251 Geyer Aug. 11, 1925 1,618,536 Junkers Feb. 22, 1927 1,776,467Frandsen Sept. 23, 1930 2,365,175 Crawford Dec. 19, 1944

